Interdigital transducer, acoustic resonator and electronic equipment

Abstract

The invention relates to an interdigital transducer, an acoustic resonator and electronic equipment. The interdigital transducer includes: a first bus bar and a second bus bar; the interdigital electrode comprises a plurality of first electrode fingers and a plurality of second electrode fingers, the first electrode fingers and the second electrode fingers are located between the first bus bar and the second bus bar, and the first electrode fingers and the second electrode fingers are oppositely arranged in the first direction in a one-to-one correspondence mode; an edge area, a spacing area, an inclined area and a central area which are arranged in the first direction are arranged between the first bus bar and the second bus bar, the inclined area is located between the central area and the spacing area, the spacing area is located between the inclined area and the edge area, and the central area is located on the side, away from the spacing area, of the inclined area; the portion, located in the inclined area, of the second electrode finger comprises a first section, a second section and a third section which are sequentially connected in the first direction, and the first section, the second section and the third section are obliquely arranged relative to the first direction.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to an interdigital transducer, an acoustic resonator and an electronic device. Background Art

[0002] The surface acoustic wave resonator includes a piezoelectric substrate and an interdigital transducer, wherein the interdigital transducer is located on one side of the piezoelectric substrate. The interdigital transducer includes a bus bar and interdigital electrodes. The piezoelectric material in the piezoelectric substrate has a piezoelectric effect, which can realize the mutual conversion of electrical signals and sound waves. The surface acoustic wave is excited by the interaction between the interdigital electrodes and the piezoelectric material, and the surface acoustic wave resonator can be constructed by utilizing the resonance characteristics of the surface acoustic wave.

[0003] With the continuous development of communication technology, higher requirements are placed on the performance of resonators, namely higher operating frequency, higher Q value and larger bandwidth. In addition to energy leakage in the vertical direction, the resonator will produce certain transverse modes and energy leakage in the horizontal direction of the electrode. The transverse modes appear in the form of spurious, which are manifested as some stray peaks in the absolute value of the resonator admittance curve. The frequencies of these transverse modes are generally distributed within the band of the resonator, that is, between the resonant frequency and the anti-resonant frequency, which will cause the deterioration of indicators such as in-band ripple, in-band flatness and insertion loss, seriously affecting the performance of the resonator. Summary of the invention

[0004] Based on this, it is necessary to provide an interdigital transducer, an acoustic resonator and an electronic device that can improve the influence of the lateral mode excited in the acoustic resonator in order to solve the above problems.

[0005] An interdigital transducer, comprising:

[0006] The first bus bar and the second bus bar are spaced apart and arranged opposite to each other along a first direction; and

[0007] an interdigitated electrode, comprising a plurality of first electrode fingers and a plurality of second electrode fingers located between the first bus bar and the second bus bar, wherein each of the first electrode fingers and each of the second electrode fingers are arranged opposite to each other in the first direction in a one-to-one correspondence; one of the first electrode fingers and the second electrode fingers arranged opposite to each other in the first direction is connected to the first bus bar, and the other of the first electrode fingers is connected to the second bus bar;

[0008] Wherein, the first bus bar and the second bus bar include an edge area, a spacing area, an inclined area and a central area arranged along the first direction, the inclined area is located between the central area and the spacing area, the spacing area is located between the inclined area and the edge area, and the central area is located on a side of the inclined area away from the spacing area;

[0009] The first electrode fingers are located in the edge area, the second electrode fingers are located in the edge area, the spacing area and the central area and are parallel to the first direction, the second electrode fingers are located in the inclined area and include a first segment, a second segment and a third segment sequentially connected along the first direction, the first segment, the second segment and the third segment are all inclined relative to the first direction, and the second segment is inclined in an opposite direction to the first segment and the third segment relative to the first direction.

[0010] In some embodiments, the portion of the second electrode finger located in the central area is a central segment, and two sides of the central segment in a second direction perpendicular to the first direction are a first side and a second side respectively;

[0011] One end of the first section facing away from the second section is connected to the central section, the first section is inclined toward the first side of the central section relative to the central section, the second section is inclined toward the second side of the central section relative to the first section, and the third section is inclined toward the first side of the central section relative to the second section.

[0012] In some embodiments, the first segment, the second segment, and the third segment have the same length in the first direction.

[0013] In some embodiments, two sides of the first segment in the second direction are first sides, the two first sides are parallel to each other, and the length dimension of the orthographic projection of the first side on a plane perpendicular to the first direction is a, and the length dimension of the orthographic projection of the first side on a plane perpendicular to the second direction is b;

[0014] The two sides of the second segment in the second direction are second sides, the two second sides are parallel to each other, and the length dimension of the orthographic projection of the second side on the plane perpendicular to the first direction is 2a, and the length dimension of the orthographic projection of the second side on the plane perpendicular to the second direction is b;

[0015] The two side edges of the third segment in the second direction are third side edges, the two third side edges are parallel to each other, and the length dimension of the orthographic projection of the third side edges on the plane perpendicular to the first direction is a, and the length dimension of the orthographic projection of the third side edges on the plane perpendicular to the second direction is b.

[0016] In some embodiments, the portion of the second electrode finger located in the inclined area includes N inclined units connected in sequence along the first direction, each of the inclined units includes the first segment, the second segment and the third segment connected in sequence along the first direction, and N is a positive integer greater than or equal to 1.

[0017] In some of these embodiments, N is equal to 1, 2 or 3.

[0018] In some embodiments, when N is equal to 1, 0.1p≤a≤0.15p, 0.3p≤b≤0.5p; wherein p represents the distance between the center lines of two adjacent second electrode fingers;

[0019] When N is equal to 2, 0.1p≤a≤0.15p, 0.3p≤b≤0.35p;

[0020] When N is equal to 3, 0.1p≤a≤0.12p, 0.15p≤b≤0.2p.

[0021] In some embodiments, the edge region includes a first edge region and a second edge region arranged at intervals along the first direction, the spacing region includes a first spacing region and a second spacing region arranged at intervals along the first direction, and the inclined region includes a first inclined region and a second inclined region arranged at intervals along the first direction;

[0022] The first edge area is located between the first bus bar and the first spacing area, the first inclined area is located between the first spacing area and the central area, the second edge area is located between the second bus bar and the second spacing area, and the second inclined area is located between the second spacing area and the central area.

[0023] In some embodiments, in the first edge region and the second edge region, the first electrode fingers and the second electrode fingers are alternately arranged along a second direction, and the second direction is perpendicular to the first direction.

[0024] An acoustic resonator comprises a piezoelectric substrate and an IDT as described in any one of the above embodiments, wherein the IDT is arranged on one side of the piezoelectric substrate.

[0025] An electronic device comprises the acoustic resonator as described in any one of the above embodiments.

[0026] The above-mentioned interdigital transducer, acoustic resonator and electronic device, by setting an inclined area, the part of each second electrode finger in the inclined area includes a first section, a second section and a third section which are connected in sequence and inclined relative to the first direction, and the inclination direction of the second section is opposite to the inclination direction of the first section and the third section, thereby destroying the boundary condition in the direction perpendicular to the main propagation direction of the surface acoustic wave (i.e., the first direction). Since the acoustic impedance of the first section, the second section and the third section is different from that of the second electrode finger in other areas, the surface acoustic wave can be reflected, thereby suppressing the excitation of the lateral mode and suppressing the energy on the lateral edge from leaking to the bus bar, thereby achieving the purpose of improving the Q value, and the energy is more concentrated between the interdigital electrodes, the conversion efficiency of mechanical energy and electrical energy is higher, thereby achieving the purpose of improving the electromechanical coupling coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of an interdigital transducer in one embodiment of the present application;

[0028] Figure 2 for Figure 1 The schematic diagram of the structure of the interdigital transducer shown is located in the inclined area;

[0029] Figure 3 This is a schematic structural diagram of a portion of an IDT located in an inclined area in another embodiment of the present application;

[0030] Figure 4 This is a schematic structural diagram of a portion of the interdigital transducer located in an inclined area in another embodiment of the present application;

[0031] Figure 5 Graphs showing the admittance curves of the interdigital transducer in Example 1 and the interdigital transducer in the comparative example;

[0032] Figure 6 is the Q of the IDT in Example 1 and the IDT in the comparative example bode Value change curve chart;

[0033] Figure 7 Graphs showing the admittance curves of the interdigital transducer in Example 2 and the interdigital transducer in the comparative example;

[0034] Figure 8 is the Q of the IDT in Example 2 and the IDT in the comparative example bode Value change curve chart;

[0035] Fig. 9 Schematic diagram of the structure of an acoustic resonator in one embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0037] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0041] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0042] See also Figure 1 The present application provides an interdigital transducer 100, comprising a first bus bar 10, a second bus bar 20 and interdigital electrodes (not shown). The first bus bar 10 and the second bus bar 20 are spaced and arranged opposite to each other along a first direction X. The interdigital electrodes include a plurality of first electrode fingers 30 and a plurality of second electrode fingers 40 located between the first bus bar 10 and the second bus bar 20. Each first electrode finger 30 and each second electrode finger 40 are arranged opposite to each other in the first direction X in a one-to-one correspondence. A first electrode finger 30 and a second electrode finger 40 arranged opposite to each other in the first direction X are referred to as an electrode finger group E. One of the electrode fingers in each electrode finger group E is connected to the first bus bar 10, and the other is connected to the second bus bar 20. Through the above arrangement, the first bus bar 10 can be connected to the first electrode finger 30 and the second electrode finger 40 at the same time, and the second bus bar 20 can be connected to the first electrode finger 30 and the second electrode finger 40 at the same time, so that the first bus bar 10 and the second bus bar 20 can provide electrical excitation to the first electrode finger 30 and the second electrode finger 40, and the first electrode finger 30 and the second electrode finger 40 can excite the surface acoustic wave. The main propagation direction of the surface acoustic wave is the second direction Y perpendicular to the first direction X. The component of the surface acoustic wave perpendicular to the main propagation direction forms a standing wave between the first bus bar 10 and the second bus bar 20, that is, a transverse mode, which will cause the deterioration of indicators such as in-band ripple, in-band flatness and insertion loss, and seriously affect the performance of the resonator. Specifically, the length of the second electrode finger 40 is longer than the first electrode finger 30.

[0043] The first bus bar 10 and the second bus bar 20 include an edge region A, a spacing region B, an inclined region C and a central region D arranged along the first direction X. The inclined region C is located between the central region D and the spacing region B, the spacing region B is located between the inclined region C and the edge region A, and the central region D is located on the side of the inclined region C away from the spacing region B. The first electrode finger 30 is located in the edge region A, and the second electrode finger 40 is located in the edge region A, the spacing region B, the inclined region C and the central region D. The portion of the second electrode finger 40 located in the edge region A, the spacing region B and the central region D is parallel to the first direction X, and the portion of the second electrode finger 40 located in the inclined region C includes a first section 411, a second section 412 and a third section 413 connected in sequence along the first direction X. The first section 411, the second section 412 and the third section 413 are all arranged to be inclined relative to the first direction X, and the second section 412 is inclined in the opposite direction to the first section 411 and the third section 413 relative to the first direction X. That is, if the first section 411 is tilted upward relative to the first direction X, the second section 412 is tilted downward relative to the first direction X, and the third section 413 is tilted upward relative to the first direction X. If the first section 411 is tilted downward relative to the first direction X, the second section 412 is tilted upward relative to the first direction X, and the third section 413 is tilted downward relative to the first direction X.

[0044] In this way, by setting the inclined region C, the portion of each second electrode finger 40 in the inclined region C includes a first section 411, a second section 412 and a third section 413 which are connected in sequence and inclined relative to the first direction X. The inclination direction of the second section 412 is opposite to the inclination direction of the first section 411 and the third section 413, thereby destroying the boundary condition in the direction perpendicular to the main propagation direction of the surface acoustic wave (i.e., in the first direction X). Since the acoustic impedance of the first section 411, the second section 412 and the third section 413 is different from that of the second electrode finger 40 in other regions, the surface acoustic wave can be reflected, thereby suppressing the excitation of the transverse mode and suppressing the energy on the transverse edge from leaking to the bus bar, thereby achieving the purpose of improving the Q value, and the energy is more concentrated between the interdigitated electrodes, the conversion efficiency of mechanical energy and electrical energy is higher, thereby achieving the purpose of improving the electromechanical coupling coefficient.

[0045] Specifically in the embodiment, each electrode finger group E is arranged between the first bus bar 10 and the second bus bar 20 at intervals along the second direction Y. The arrangement direction of the first electrode finger 30 and the second electrode finger 40 in any electrode finger group E is opposite to the arrangement direction of the first electrode finger 30 and the second electrode finger 40 in the adjacent electrode finger group E. Exemplarily, in a certain electrode finger group E, the first electrode finger 30 is connected to the first bus bar 10, and the second electrode finger 40 is connected to the second bus bar 20, then in an electrode finger group E adjacent to the electrode finger group E, the first electrode finger 30 is connected to the second bus bar 20, and the second electrode finger 40 is connected to the first bus bar 10.

[0046] Specifically in the embodiment, in the edge region A, the first electrode fingers 30 and the second electrode fingers 40 are arranged alternately with each other along the second direction Y. In some embodiments, the edge region A may include a first edge region A1 and a second edge region A2 arranged at intervals along the first direction X. The first edge region A1 may be adjacent to the first bus bar 10, and in the first edge region A1, the first electrode fingers 30 and the second electrode fingers 40 connected to the first bus bar 10 are arranged alternately with each other along the second direction Y. The second edge region A2 may be adjacent to the second bus bar 20, and in the second edge region A2, the first electrode fingers 30 and the second electrode fingers 40 connected to the second bus bar 20 are arranged alternately with each other along the second direction Y.

[0047] Specifically in the embodiment, the spacing space 43 between the first electrode finger 30 and the second electrode finger 40 in the same electrode finger group E is located in the spacing area B. In the spacing space 43, the second electrode finger 40 and the spacing space 43 are arranged alternately with each other along the second direction Y. In some embodiments, the spacing area B may include a first spacing area B1 and a second spacing area B2. Among them, the first spacing area B1 is adjacent to the side of the first edge area A1 away from the first bus bar 10. In the first spacing area B1, the second electrode finger 40 and the above-mentioned spacing space 43 are arranged alternately with each other along the second direction Y. The second spacing area B2 is adjacent to the side of the second edge area A2 away from the second bus bar 20. In the second spacing area B2, the second electrode finger 40 and the above-mentioned spacing space 43 are arranged alternately with each other along the second direction Y.

[0048] Specifically in the embodiment, in the central region D and the inclined region C, each second electrode finger 40 is arranged at intervals along the second direction Y. The inclined region C is located between the central region D and the spacing region B, and the spacing region B is located between the inclined region C and the edge region A. In some embodiments, the number of the inclined regions C may be two, and the two inclined regions C are respectively the first inclined region C1 and the second inclined region C2. The first inclined region C1 is located between the first spacing region B1 and the central region D, and the second inclined region C2 is located between the second spacing region B2 and the central region D.

[0049] Specific to Figure 1 In the illustrated embodiment, the edge region A includes a first edge region A1 and a second edge region A2 arranged at intervals along the first direction X, the spacing region B includes a first spacing region B1 and a second spacing region B2 arranged at intervals along the first direction X, and the inclined region C includes a first inclined region C1 and a second inclined region C2 arranged at intervals along the first direction X.

[0050] The first edge region A1 is located between the first bus bar 10 and the first spacing region B1, and the first inclined region C1 is located between the first spacing region B1 and the central region D. The second edge region A2 is located between the second bus bar 20 and the second spacing region B2, and the second inclined region C2 is located between the second spacing region B2 and the central region D. Parts of the second electrode fingers 40 connected to the first bus bar 10 in the first edge region A1, the first spacing region B1 and the central region D are all parallel to the first direction X, and parts of the second electrode fingers 40 connected to the second bus bar 20 in the second edge region A2, the second spacing region B2 and the central region D are all parallel to the first direction X. Parts of the second electrode fingers 40 in the first inclined region C1 and the second inclined region C2 include a first segment 411, a second segment 412 and a third segment 413 sequentially connected along the first direction X, and the first segment 411, the second segment 412 and the third segment 413 are all arranged obliquely relative to the first direction X.

[0051] Please continue to see Figure 1 In the embodiment of the present application, the portion of the second electrode finger 40 located in the central area D is the central segment 42, which is parallel to the first direction X, and has a first side 421 and a second side 422 on both sides in the second direction Y. The end of the first segment 411 away from the second segment 412 is connected to the central segment 42. The first segment 411 is inclined toward the first side 421 of the central segment 42 relative to the central segment 42. The second segment 412 is inclined toward the second side 422 of the central segment 42 relative to the first segment 411. The third segment 413 is inclined toward the first side 421 of the central segment 42 relative to the second segment 412. Further, the lengths of the first segment 411, the second segment 412, and the third segment 413 in the first direction X are equal.

[0052] See also Figure 2 As shown, specifically in the embodiment, the two sides of the first section 411 in the second direction Y are first side sides 4110, and the two first side sides 4110 are parallel to each other and are inclined relative to the first direction X and the second direction Y. The length dimension of the orthographic projection of each first side side 4110 on a plane perpendicular to the first direction X is a, and the length dimension of the orthographic projection on a plane perpendicular to the second direction Y is b.

[0053] The two sides of the second section 412 in the second direction Y are second sides 4120. The two second sides 4120 are parallel to each other and are arranged obliquely to the first direction X and the second direction Y. The length dimension of the orthographic projection of each second side 4120 on a plane perpendicular to the first direction X is 2a, and the length dimension of the orthographic projection on a plane perpendicular to the second direction Y is b.

[0054] The two sides of the third section 413 in the second direction Y are third sides 4130, and the two third sides 4130 are parallel to each other and are arranged obliquely with respect to both the first direction X and the second direction Y. The length dimension of the orthographic projection of each third side 4130 on a plane perpendicular to the first direction X is a, and the length dimension of the orthographic projection on a plane perpendicular to the second direction Y is b.

[0055] See also Figures 2 to 4 As shown, specifically in the embodiment, the portion of the second electrode finger 40 located in the inclined region C (i.e., the first inclined region C1 or the second inclined region C2) includes N inclined units 41 sequentially connected along the first direction X, and each inclined unit 41 includes a first segment 411, a second segment 412, and a third segment 413 sequentially connected along the first direction X. Wherein, N is a positive integer greater than or equal to 1. That is, the portion of the second electrode finger 40 located in the first inclined region C1 includes at least one inclined unit 41, and each inclined unit 41 includes the above-mentioned first segment 411, the second segment 412, and the third segment 413 sequentially connected along the first direction X; or, the portion of the second electrode finger 40 located in the second inclined region C2 includes at least one inclined unit 41, and each inclined unit 41 includes the above-mentioned first segment 411, the second segment 412, and the third segment 413 sequentially connected along the first direction X.

[0056] Optionally, N is equal to 1, 2, or 3. See Figure 2 As shown, when N is equal to 1, the portion of the second electrode finger 40 located in the first inclined region C1 includes an inclined unit 41, and the inclined unit 41 includes the above-mentioned first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X; and / or, the portion of the second electrode finger 40 located in the second inclined region C2 includes an inclined unit 41, and the inclined unit 41 includes the above-mentioned first segment 411, the second segment 412 and the third segment 413 connected in sequence along the first direction X.

[0057] See also Figure 3As shown, when N is equal to 2, the portion of the second electrode finger 40 located in the first inclined region C1 includes two inclined units 41 sequentially connected along the first direction X, and each inclined unit 41 includes the above-mentioned first segment 411, second segment 412 and third segment 413 sequentially connected along the first direction X, that is, the portion of the second electrode finger 40 located in the first inclined region C1 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412 and the third segment 413 sequentially connected; and / or, the portion of the second electrode finger 40 located in the second inclined region C2 includes two inclined units 41 sequentially connected along the first direction X, and each inclined unit 41 includes the above-mentioned first segment 411, the second segment 412 and the third segment 413 sequentially connected along the first direction X, that is, the portion of the second electrode finger 40 located in the second inclined region C2 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412 and the third segment 413 sequentially connected along the first direction X.

[0058] See also Figure 4 As shown, when N is equal to 3, the portion of the second electrode finger 40 located in the first inclined region C1 includes three inclined units 41 sequentially connected along the first direction X, and each inclined unit 41 includes the first segment 411, the second segment 412, and the third segment 413 sequentially connected along the first direction X. That is, the portion of the second electrode finger 40 located in the first inclined region C1 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412, and the third segment 413 sequentially connected along the first direction X. 13; and / or, the portion of the second electrode finger 40 located in the second inclined area C2 includes three inclined units 41 sequentially connected along the first direction X, and each inclined unit 41 includes the above-mentioned first segment 411, second segment 412 and third segment 413 sequentially connected along the first direction X, that is, the portion of the second electrode finger 40 located in the second inclined area C2 includes the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412, the third segment 413, the first segment 411, the second segment 412 and the third segment 413 sequentially connected along the first direction X.

[0059] It should be noted that the inventor of the present application has creatively discovered through long-term practice that the inclination angle θ of the first section 411 relative to the first direction X should not be too large or too small, and the length W0 of the portion of the second electrode finger 40 located in the inclined region C in the first direction X should not be too large or too small. Too small θ and W0 will result in the suppression of the lateral mode and the effect of improving the Q value and the electromechanical coupling coefficient being not obvious. Too large θ and W0 will lead to the excitation of new modes and will not meet the design requirements of miniaturization. θ represents the inclination angle of the first section 411 relative to the first direction X, tanθ=a / b, the larger a / b is, the larger θ is; conversely, the smaller a / b is, the smaller θ is. W0 represents the length of the portion of the second electrode finger 40 located in the inclined region C in the first direction X, so W0=N×3b, the larger b is, the larger W0 is; conversely, the smaller b is, the smaller W0 is. Therefore, the values ​​of θ and W0 can be controlled by controlling the values ​​of a and b.

[0060] See also Figure 2 , Optionally, in an embodiment where N is equal to 1, a and b satisfy: 0.1p≤a≤0.15p, 0.3p≤b≤0.5p. Wherein, p represents the interdigital pitch pitch, that is, the distance between the center lines of two adjacent second electrode fingers 40. In this way, by controlling the values ​​of a and b, the values ​​of θ and W0 are moderate, ensuring that the new mode is avoided from being excited while the performance of the resonator is significantly improved, and better meeting the design requirements of miniaturization.

[0061] See also Figure 3 , Optionally, in an embodiment where N is equal to 2, a and b satisfy: 0.1p≤a≤0.15p, 0.3p≤b≤0.35p. In this way, by controlling the values ​​of a and b, the values ​​of θ and W0 are moderate, ensuring that the performance of the resonator is significantly improved while avoiding the excitation of new modes, and better meeting the design requirements of miniaturization. Preferably, a is equal to 0.15μm, and b is equal to 0.35μm.

[0062] See also Figure 4 , Optionally, in the embodiment where N is equal to 3, a and b satisfy: 0.1p≤a≤0.12p, 0.15p≤b≤0.2p. In this way, by controlling the values ​​of a and b, the values ​​of θ and W0 are moderate, ensuring that the performance of the resonator is significantly improved while avoiding the excitation of new modes, and better meeting the design requirements of miniaturization. a is equal to 0.1μm, and b is equal to 0.15μm.

[0063] In order to illustrate the beneficial effects of the interdigital transducer 100 in the present application, the comparative example and the embodiment of the present application are compared and described below:

[0064] In Example 1, the interdigital transducer 100 in the present application is used to construct a resonator, and N is equal to 2, that is, the second electrode finger 40 located in the first inclined region C1 and the second inclined region C2 includes two inclined units 41 sequentially connected along the first direction X, and each inclined unit 41 includes a first section 411, a second section 412 and a third section 413 sequentially connected along the first direction X. a is equal to 0.15 μm, and b is equal to 0.35 μm.

[0065] In Example 2, the interdigital transducer 100 in the present application is used to construct a resonator, and N is equal to 3, that is, the second electrode finger 40 located in the first inclined region C1 and the second inclined region C2 includes three inclined units 41 sequentially connected along the first direction X, and each inclined unit 41 includes a first section 411, a second section 412 and a third section 413 sequentially connected along the first direction X. a is equal to 0.1 μm, and b is equal to 0.15 μm.

[0066] The difference between the IDT used in the comparative example and the embodiments 1 and 2 is that the second electrode fingers do not include the tilting unit 41 , that is, the second electrode fingers are parallel to the first direction X in each region.

[0067] Figure 5 The admittance curves of the IDT 100 in Example 1 and the IDT in the comparative example are shown. Figure 6 The Q of the IDT 100 in Example 1 and the IDT in the comparative example is shown. bode The value change curve. Figure 7 The admittance curves of the IDT 100 in Example 2 and the IDT in the comparative example are shown. Figure 8 The Q of the IDT 100 in Example 2 and the IDT in the comparative example is shown. bode The value change curve.

[0068] Table 1: Comparison of performance parameters of the IDT 100 in the comparative example, embodiment 1 and embodiment 2

[0069] Electromechanical coupling coefficient kt2 <![CDATA[Q bode (max)]]> Comparative Example 7.73％ 1680 Example 1 8.17％ 1631 Example 2 8.06％ 1692

[0070] from Figure 5 and Figure 7 It can be seen from the figure that the resonance point and anti-resonance point frequencies of the admittance curves of Example 1 and Example 2 are significantly shifted, so that the electromechanical coupling coefficient k t 2 It can be seen from Table 1 that compared with the comparative example, the electromechanical coupling coefficient k in Example 1 is t 2 The electromechanical coupling coefficient k in Example 2 increased by 5.69%. t 2 It increased by 4.27%. Figure 6 , Figure 8 As can be seen from Table 1, compared with the comparative example, Q bode The maximum value of is increased by 12.

[0071] From the perspective of the frequency offset between the resonance point and the anti-resonance point, the resonator constructed using Example 1 or Example 2 will have a bandwidth improvement of 3MHz. B34 (2010-2025MHz) and B39 (1880-1920MHz) are one of the main frequency bands for time division duplex (TDD) in operator applications, and the corresponding SAW resonators are widely used in mobile phone RF front-end receiving circuits. For commercial resonators, in the frequency band around 2GHz, the 3MHz bandwidth improvement can improve the insertion loss at the edge of the working frequency band by 0.1-0.3dB, which greatly supports resonator design, process margin, etc., and significantly helps to improve the competitiveness of commercial resonators.

[0072] In summary, the IDT 100 in Examples 1 and 2 has significant effects on improving the electromechanical coupling coefficient and extending the bandwidth. The IDT 100 in Example 2 can improve the Q value, thereby achieving the purpose of improving the performance of the resonator, and providing strong support for the subsequent development of high-performance resonators.

[0073] On the other hand, according to the above-mentioned IDT 100, the present application also provides an acoustic resonator. The acoustic resonator includes a piezoelectric substrate 200 and the IDT 100 as described in any of the above embodiments, and the IDT 100 is located on one side of the piezoelectric substrate 200. The material of the IDT 100 may include one or more of aluminum, copper, titanium, gold, silver, platinum, and molybdenum; or, the material of the IDT 100 may also be other alloy materials.

[0074] The piezoelectric material in the piezoelectric substrate 200 has a piezoelectric effect, which can realize the mutual conversion between electrical signals and sound waves. The surface acoustic wave is excited by the interaction between the interdigital transducer 100 and the piezoelectric substrate 200, and a SAW resonator (surface-acoustic-wave) can be constructed by utilizing the resonance characteristics of the surface acoustic wave.

[0075] On the other hand, according to the above acoustic resonator, the present application also provides an electronic device. The electronic device includes the acoustic resonator described in any of the above embodiments. It should be noted that the electronic device can be an intermediate product such as a radio frequency front end, a filter amplifier module, etc.; or, the electronic device can also be a terminal product such as a mobile phone, a tablet computer, a drone, etc., which is not limited here.

[0076] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. An interdigital transducer, characterized in that: include: The first bus bar (10) and the second bus bar (20) are arranged opposite to each other at intervals along a first direction (X); and An interdigitated electrode, comprising a plurality of first electrode fingers (30) and a plurality of second electrode fingers (40) located between the first bus bar (10) and the second bus bar (20), wherein each of the first electrode fingers (30) and each of the second electrode fingers (40) are arranged opposite to each other in a one-to-one correspondence in the first direction (X); among the first electrode fingers (30) and the second electrode fingers (40) arranged opposite to each other in the first direction (X), one of them is connected to the first bus bar (10), and the other of them is connected to the second bus bar (20); Wherein, the first bus bar (10) and the second bus bar (20) include an edge region (A), a spacing region (B), an inclined region (C) and a central region (D) arranged along the first direction (X), the inclined region (C) is located between the central region (D) and the spacing region (B), the spacing region (B) is located between the inclined region (C) and the edge region (A), and the central region (D) is located on a side of the inclined region (C) away from the spacing region (B); The first electrode finger (30) is located in the edge region (A); the second electrode finger (40) is located in the edge region (A), the spacing region (B) and the central region (D) and is parallel to the first direction (X); the second electrode finger (40) is located in the inclined region (C) and includes a first segment (411), a second segment (412) and a third segment (413) which are sequentially connected along the first direction (X); the first segment (411), the second segment (412) and the third segment (413) are all arranged to be inclined relative to the first direction (X); and the second segment (412) is inclined in an opposite direction to the first segment (411) and the third segment (413) relative to the first direction (X).

2. The interdigital transducer according to claim 1, characterized in that: The portion of the second electrode finger (40) located in the central area (D) is a central segment (42), and two sides of the central segment (42) in a second direction (Y) perpendicular to the first direction (X) are respectively a first side (421) and a second side (422); One end of the first section (411) facing away from the second section (412) is connected to the central section (42); the first section (411) is inclined toward the first side (421) of the central section (42) relative to the central section (42); the second section (412) is inclined toward the second side (422) of the central section (42) relative to the first section (411); and the third section (413) is inclined toward the first side (421) of the central section (42) relative to the second section (412).

3. The interdigital transducer according to claim 2, characterized in that: The lengths of the first section (411), the second section (412) and the third section (413) in the first direction (X) are equal.

4. The interdigital transducer according to claim 3, characterized in that: The two sides of the first section (411) in the second direction (Y) are first sides (4110), the two first sides (4110) are parallel to each other, and the length dimension of the orthographic projection of the first side (4110) on a plane perpendicular to the first direction (X) is a, and the length dimension of the orthographic projection on a plane perpendicular to the second direction (Y) is b; The two sides of the second section (412) in the second direction (Y) are second sides (4120), the two second sides (4120) are parallel to each other, and the length dimension of the orthographic projection of the second side (4120) on a plane perpendicular to the first direction (X) is 2a, and the length dimension of the orthographic projection on a plane perpendicular to the second direction (Y) is b; The two side edges of the third section (413) in the second direction (Y) are third side edges (4130), the two third side edges (4130) are parallel to each other, and the length dimension of the orthographic projection of the third side edge (4130) on a plane perpendicular to the first direction (X) is a, and the length dimension of the orthographic projection on a plane perpendicular to the second direction (Y) is b.

5. The interdigital transducer according to claim 4, characterized in that: The portion of the second electrode finger (40) located in the inclined region (C) comprises N inclined units (41) sequentially connected along the first direction (X), each of the inclined units (41) comprises the first segment (411), the second segment (412) and the third segment (413) sequentially connected along the first direction (X), and N is a positive integer greater than or equal to 1.

6. The interdigital transducer according to claim 5, characterized in that: N is equal to 1, 2 or 3.

7. The interdigital transducer according to claim 6, characterized in that: When N is equal to 1, 0.1p≤a≤0.15p, 0.3p≤b≤0.5p; wherein p represents the distance between the center lines of two adjacent second electrode fingers (40); When N is equal to 2, 0.1p≤a≤0.15p, 0.3p≤b≤0.35p; When N is equal to 3, 0.1p≤a≤0.12p, 0.15p≤b≤0.2p.

8. The interdigital transducer according to any one of claims 1 to 7, characterized in that: The edge region (A) includes a first edge region (A1) and a second edge region (A2) arranged at intervals along the first direction (X), the spacing region (B) includes a first spacing region (B1) and a second spacing region (B2) arranged at intervals along the first direction (X), and the inclined region (C) includes a first inclined region (C1) and a second inclined region (C2) arranged at intervals along the first direction (X); The first edge area (A1) is located between the first bus bar (10) and the first spacing area (B1), the first inclined area (C1) is located between the first spacing area (B1) and the center area (D), the second edge area (A2) is located between the second bus bar (20) and the second spacing area (B2), and the second inclined area (C2) is located between the second spacing area (B2) and the center area (D).

9. The interdigital transducer according to claim 8, characterized in that: In the first edge region (A1) and the second edge region (A2), the first electrode fingers (30) and the second electrode fingers (40) are alternately arranged along a second direction (Y), and the second direction (Y) is perpendicular to the first direction (X).

10. An acoustic resonator, comprising a piezoelectric substrate (200) and the interdigital transducer (100) according to any one of claims 1 to 9, wherein the interdigital transducer (100) is arranged on one side of the piezoelectric substrate (200).

11. An electronic device comprising the acoustic resonator according to claim 10.

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